Gate Tunable Josephson Diode in Proximitized InAs Supercurrent Interferometers

Abstract

The Josephson diode (JD) is a non-reciprocal circuit element that supports a larger critical current in one direction compared to the other. This effect has gained a growing interest because of promising applications in superconducting electronic circuits with low power consumption. Some implementations of a JD rely on breaking the inversion symmetry in the material used to realize Josephson junctions (JJs), but a recent theoretical proposal has suggested that the effect can also be engineered by combining two JJs hosting highly transmitting Andreev bound states in a Superconducting Quantum Interference Device (SQUID) at a small, but finite flux bias [1]. We realized a SQUID with two JJs fabricated in a proximitized InAs two-dimensional electron gas (2DEG). We demonstrate gate control of the diode efficiency from zero up to around $30$\% for different flux biases which comes close to the maximum of $\sim 40$\% predicated in Ref. [1]. The key ingredient to the JD effect in the SQUID arrangement is the presence of an asymmetry between the two SQUID arms.Comment: 9+8 pages, 3+6 figures (main text + supplementary